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DDD basics

Use ubiquitous language, bounded contexts, aggregates, and domain services where business complexity is high enough to justify the modeling cost.

Domain-Driven Design aligns code with business language through ubiquitous language, bounded contexts, aggregates, entities, value objects, and domain services. It pays off when rules are rich, contested, and long-lived—not for every CRUD admin screen. Strategic design (contexts, relationships) matters as much as tactical patterns.

On interviews: explain when DDD is worth the modeling cost. Walk through ubiquitous language example and context map sketch.

Common pitfalls: DDD jargon without collaboration with domain experts; aggregates too large or too small; anemic models with all logic in application services.

Checklist:

  • Glossary shared with product and stakeholders.
  • Bounded contexts named by business capability.
  • Aggregates enforce consistency boundaries.
  • Context integration patterns chosen explicitly.